Structural control, alteration and primary mineralization at the Big Springs gold mine, Elko County, Nevada

Online access for this thesis was created in part with support from the Institute of Museum and Library Services (IMLS) administered by the Nevada State Library, Archives and Public Records through the Library Services and Technology Act (LSTA). To obtain a high quality image or document please contact the DeLaMare Library at https://unr.libanswers.com/ or call: 775-784-6945.The Big Springs Gold Mine is located in the Independence Mountains in northern Elko County. The mine is a sediment hosted disseminated gold deposit within Pennsylvanian to Mississippian age siltstones of the Schoonover formation. Gold mineralization is tightly structurally controlled. Ore structures are predominately east-west striking north dipping normal faults formed during Pre-Basin and Range extension. Alteration consists of dolomitization, sericitization, decalcification, and silicification. Gold is deposited syn or post genetically with decalcification and silicification. Gold occurs as free grains, up to seven microns in size, within the edges of arsenical pyrite as well as encapsulated in silica within the siltstone matrix. Arsenic, antimony, mercury, thallium, and cadmium are all associated with gold in the ore zones with cadmium and thallium showing the best correlation to gold